Monohydric polyfluorooxetane oligomers, polymers, and copolymers and coating containing the same
View Patent ↗Monofunctional polyfluorooxetane oligomers, polymers, and copolymers are prepared by the cationic polymerization of fluorooxetane monomers with a monoalcohol. In addition to serving as an initiator, the monoalcohol can also serve as a solvent for the fluorooxetane or other monomers to produce oligomers, polymers, or copolymers having low cyclic content. Suitable comonomers generally include various cyclic ethers. The polyfluorooxetane oligomer, polymer, or copolymer having a single hydroxyl end group can be functionalized with a variety of compounds so as to yield a functional end group such as an acrylate, a methacrylate, an allylic, an amine, etc., with the functionalized oligomer or polymer being suitable for use in radiation curable or thermal curable coating compositions. These functionalized polymers can be copolymerized and cured to provide improvements in wetting and surface properties.
1. A process for forming a monohydric polyfluorooxetane composition, comprising the steps of:
reacting a monoalcohol with a monomer consisting essentially of a fluorooxetane monomer in the presence of a Lewis acid catalyst, and forming an oligomer or homonolymer.
2. A process according to claim 1 , wherein said monoalcohol comprises an organic alcohol, a polymeric alcohol, a tetrafluoroethylene based telomer fluoroalcohol, or combinations thereof,
wherein said fluorooxetane monomer has the formula
or combinations thereof, where each n is the same or different and independently is an integer from 1 to about 6, R is hydrogen or an alkyl of 1 to 6 carbon atoms, and each Rf is the same or different and independently on each repeat unit is a linear or branched fluorinated alkyl of 1 to 20 carbon atoms, a minimum of 75 percent of the non-carbon atoms of the alkyl being fluorine atoms and optionally the remaining non-carbon atoms being H, I, Cl, or Br; or each Rf is the same or different and independently is a perfluorinated polyether having from 4 to 60 carbon atoms.
3. A process according to claim 2 , wherein said organic alcohol has from 1 to 40 carbon atoms, wherein said polymeric alcohol contains repeat units derived from an alkylene oxide having from 2 to 6 carbon atoms wherein the number of repeat groups is from about 3 to about 30, and wherein said tetrafluoroethylene based telomer is CF 3 CF 2 (CF 2 CF 2 ) x CH 2 CH 2 OH where x is from 1 to about 19, and wherein the number of repeat units in said oligomer or opolymer is from 2 to about 150.
4. A process according to claim 3 , including conducting said reaction in a solution substantially free of a non-initiator solvent, wherein the number of repeat units in said oligomer or polymer is from about 2 to about 50, wherein each Rf is the same or different and independently is a linear or branch fluorinated alkyl having from 1 to about 15 carbon atoms, wherein said fluorooxetane monomers are polymerized at a temperature of from about 0° C. to about 100° C., wherein in said cationic catalyst is a complex of boron trifluoride-tetrahydrofur-an, and wherein said monoalcohol is benzyl alcohol, trifluoroethanol, allylic alcohol, heptafluorobutanol, pentafluoropropanol, pentafluorobutanol, nona fluorohexanol, various perfluoroalkylethanols, or combinations thereof, and wherein the amount of any non-initiator solvent is about 5% by weight or less based upon the total weight of said non-initiator solvent and said monoalcohol.
5. A process according to claim 4 , wherein said fluorooxetane monomer is said
where R is methyl or ethyl, wherein n is 1 to about 3, and wherein Rf contains from 1 to 8 carbon atoms and has at least 85% of the non-carbon atoms being fluorine atoms, and wherein the number of repeat groups of said oligomer or polymer is from about 2 to about 20.
6. A process according to claim 1 , wherein said composition contains an amount of cyclic oligomer which is less than about 10% by weight based upon the total weight of said polyfluorooxetane oligomer or polymer.
7. A process according to claim 3 , wherein said composition contains an amount of cyclic oligomer which is less than about 5% by weight based upon the total weight of said polyfluorooxetane oligomer or polymer.
8. A process according to claim 5 , wherein said composition contains an amount of cyclic oligomer which is less than about 2% or less by weight based upon the total weight of said polyfluorooxetane oligomer or polymer.
9. A process according to claim 1 , wherein the step of reacting is performed in the presence of less than about 25 percent by weight non-initiator solvent, based upon the total weight of non-initiator solvent and the monoalcohol.